Iowa farmers are now officially in planting season. "We've had some interesting weather getting here," says Raymond Duncan, a Keokuk County farmer. "It's an important time of year, when we are planting the corn. Little mistakes done at this time can really come back to haunt you later on. This is really the time to pay attention to details. One thing is planting date. The risk of planting corn too early is great. We've seen that with some corn that was planted earlier this spring—it got frosted. Another thing to watch is soil compaction. Planting when the soil is ready is very important to avoid creating problems that the corn will have to live with."
Last week there was rain in much of the state. "The temptation for some farmers might be to try to get corn in the ground a little too soon, before the soil has dried out enough," says Jim Fawcett, Iowa State University Extension agronomist for east central and southeast Iowa. "Be sure to wait until the soil moisture content is appropriate before you pull into a field and plant corn."
Bottom line: wait until soil moisture content is appropriate to be planting
"This is one thing you definitely don't want to do. Don't plant corn when the soil is too wet. You can get sidewall compaction, where the planter actually causes some smearing of the soil. And then the roots don't grow through that compacted soil. You can wind up with rootless corn or potassium deficiency." The potassium deficiency is caused by corn roots in compacted soils not being able to take up potassium.
Another thing Fawcett sees problems with every year is some farmers planting corn too shallow. "I would always err on the deep side when planting corn," he says. "That is, you should shoot for a two inch planting depth. Planting an inch and a half is okay, but if you shoot for an inch and a half and wind up with a one-inch planting depth, you can run into problems with rootless corn or similar problems. My bias is to always shoot for a 2-inch planting depth for corn. That can avoid potential problems that can otherwise show up later."
Plant right corn population, so you can take advantage of seed technology
What about corn plant population? What mistake to farmers often make with plant population? Make sure you plant the population that's recommended for your corn hybrid. "One thing we've seen in recent years is the recommended population has increased a little every year," says Fawcett. "The yield increase we've seen over the years is because corn breeders have bred the corn so that it can withstand higher populations. So if you aren't planting at those higher populations you really aren't taking advantage of the seed technology that you have and that you are paying for."
What about cutworm on emerging corn? Is this insect a threat this spring?
Iowa saw flights of black cutworm moths come into the state earlier than normal this spring when it was so unusually warm. But since then we've had colder temperatures-- in some areas down to 25 degrees F or slightly lower. Does that colder weather reduce any potential problems with cutworms that may have been in the area?
"It depends on when the black cutworm moths may have entered your area," says Fawcett. "These cutworm moths fly into Iowa from the south early each spring and lay eggs in fields. The moths are attracted by tiny weed seedlings as a place for the moths to lay their eggs and the eggs eventually hatch into cutworms—which can clip off the young corn plants."
Whether or not your area of the state or your corn fields have cutworm problems this spring will depend on when the cutworm moths flew in. Fawcett thinks this year is going to be difficult to use the moth flights as a good indicator. "I think if I were a farmer I would be out there in the field, scouting my corn as it is coming up, and keep an eye on it just to see if we do have a cutworm problem. But normally when you get down to that temperature, to 25 degrees or so, the moths that haven't laid their eggs yet, they will die. The bottom line is, it's been such a weird spring weather-wise, I'd be watching for cutworms in fields regardless of what our adult moth traps tell us this year."
Scouting your fields is important when corn is emerging and getting established
Scouting your fields is very important regardless of what has occurred with the weather and cutworm moth flights. "As soon as the corn starts to emerge from the ground I would definitely be doing some scouting of my fields," advises Fawcett. "We have had early moth flights than normal this spring and it's going to be harder to predict cutworm problems this year because of the unusual weather we've had."
Final thought: The main thing is to take some extra time in the spring and scout your corn. And don't get in a rush to plant your corn. Pay attention to details like planting depth and soil conditions. Also watch the planter speed. Some people try to plant too fast and don't get a good stand of corn, notes Fawcett.
A lot of areas that needed rain in Iowa got a good rain last week. Some areas that needed rain didn't get but a trace. And some areas that needed rain got too much. "Where I'm located in the Cedar Rapids-Iowa City area, we got two inches. It came down a little too fast, and did cause some soil erosion," says Fawcett. "But that rain was what we needed because it's been so dry since last fall. It would have been better to have received that rain last weekend if it would have fallen in a 24-hour period rather than in the one or two hours that it all came down in."